2020 LD is an
Apollo
Apollo, grc, Ἀπόλλωνος, Apóllōnos, label=genitive , ; , grc-dor, Ἀπέλλων, Apéllōn, ; grc, Ἀπείλων, Apeílōn, label=Arcadocypriot Greek, ; grc-aeo, Ἄπλουν, Áploun, la, Apollō, la, Apollinis, label= ...
near-Earth asteroid
A near-Earth object (NEO) is any small Solar System body whose orbit brings it into proximity with Earth. By convention, a Solar System body is a NEO if its closest approach to the Sun (perihelion) is less than 1.3 astronomical units (AU) ...
roughly in diameter. It was discovered on 7 June 2020 when the asteroid was about from Earth and had a
solar elongation
In astronomy, a planet's elongation is the angular separation between the Sun and the planet, with Earth as the reference point. The greatest elongation of a given inferior planet occurs when this planet's position, in its orbital path around ...
of 154 degrees. The glare of the Sun had masked the approach of the asteroid since November 2019.
The asteroid passed closest approach to Earth on 5 June 2020 at a distance of .
[ The close approach distance is now known with an accuracy of roughly ± 1000 km. This is the largest asteroid to pass closer than the Moon this year and possibly the largest since in November 2011. The asteroid makes close approaches to Mercury, ]Venus
Venus is the second planet from the Sun. It is sometimes called Earth's "sister" or "twin" planet as it is almost as large and has a similar composition. As an interior planet to Earth, Venus (like Mercury) appears in Earth's sky never f ...
, Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surf ...
, and Mars
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury. In the English language, Mars is named for the Roman god of war. Mars is a terrestrial planet with a thin atmos ...
.[ It will be brighter than apparent magnitude 24 until 18 July 2020.
With a short 6 day ]observation arc
In observational astronomy, the observation arc (or arc length) of a Solar System body is the time period between its earliest and latest observations, used for tracing the body's path. It is usually given in days or years. The term is mostly use ...
it was possible that the asteroid had passed from Earth in June 1918 or would pass from Venus in April 2024.[
With a 11-day observation arc, the ]Sentry Risk Table
Sentry is a highly automated impact prediction system operated by the JPL Center for NEO Studies (CNEOS) since 2002. It continually monitors the most up-to-date asteroid catalog for possibilities of future impact with Earth over the next 100+ y ...
lists a 1 in 9 million chance of impact on 7 June 2109.[
is another similarly sized asteroid whose close approach will not be masked by the Sun this year.
]
Recent 100m asteroids passing inside lunar distance
Very few asteroids have known sizes or shapes. The albedo
Albedo (; ) is the measure of the diffuse reflection of solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body that refl ...
(how reflective the surface is) of these asteroids is often unknown and therefore only generic assumptions can be made about their sizes. A smaller more reflective asteroid can have the same absolute magnitude
Absolute magnitude () is a measure of the luminosity of a celestial object on an inverse logarithmic astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent magnitude that the object would have if it we ...
(H) of a larger less reflective asteroid.
See also
* 2019 OK
2019 OK is a near-Earth asteroid noted for its sudden, surprise discovery on the day before its close flyby in 2019. The object's size is estimated at across, the closest asteroid of such size discovered in 2019. It is uncommon for asteroids of ...
* 2018 AH
2018 AH is a sub-kilometer asteroid, classified as near-Earth object of the Apollo group, approximately in diameter. It was first observed on 4 January 2018, by the Asteroid Terrestrial-impact Last Alert System (ATLAS) on Mauna Loa and quickly f ...
Notes
References
External links
Biggest asteroid to pass close (and undetected) this year
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Minor planet object articles (unnumbered)
Discoveries by ATLAS
Potential impact events caused by near-Earth objects
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